12,702 research outputs found
Partial Strong Converse for the Non-Degraded Wiretap Channel
We prove the partial strong converse property for the discrete memoryless
\emph{non-degraded} wiretap channel, for which we require the leakage to the
eavesdropper to vanish but allow an asymptotic error probability to the legitimate receiver. We show that when the transmission rate is
above the secrecy capacity, the probability of correct decoding at the
legitimate receiver decays to zero exponentially. Therefore, the maximum
transmission rate is the same for , and the partial strong
converse property holds. Our work is inspired by a recently developed technique
based on information spectrum method and Chernoff-Cramer bound for evaluating
the exponent of the probability of correct decoding
Capacity Region of Finite State Multiple-Access Channel with Delayed State Information at the Transmitters
A single-letter characterization is provided for the capacity region of
finite-state multiple access channels. The channel state is a Markov process,
the transmitters have access to delayed state information, and channel state
information is available at the receiver. The delays of the channel state
information are assumed to be asymmetric at the transmitters. We apply the
result to obtain the capacity region for a finite-state Gaussian MAC, and for a
finite-state multiple-access fading channel. We derive power control strategies
that maximize the capacity region for these channels
On the capacity of memoryless finite-state multiple-access channels with asymmetric state information at the encoders
A single-letter characterization is provided for the capacity region of
finite-state multiple-access channels, when the channel state process is an
independent and identically distributed sequence, the transmitters have access
to partial (quantized) state information, and complete channel state
information is available at the receiver. The partial channel state information
is assumed to be asymmetric at the encoders. As a main contribution, a tight
converse coding theorem is presented. The difficulties associated with the case
when the channel state has memory are discussed and connections to
decentralized stochastic control theory are presented.Comment: 8 pages, 1 figure, accepted for publication, in pres
Vector Broadcast Channels: Optimality of Threshold Feedback Policies
Beamforming techniques utilizing only partial channel state information (CSI)
has gained popularity over other communication strategies requiring perfect CSI
thanks to their lower feedback requirements. The amount of feedback in
beamforming based communication systems can be further reduced through
selective feedback techniques in which only the users with channels good enough
are allowed to feed back by means of a decentralized feedback policy. In this
paper, we prove that thresholding at the receiver is the rate-wise optimal
decentralized feedback policy for feedback limited systems with prescribed
feedback constraints. This result is highly adaptable due to its distribution
independent nature, provides an analytical justification for the use of
threshold feedback policies in practical systems, and reinforces previous work
analyzing threshold feedback policies as a selective feedback technique without
proving its optimality. It is robust to selfish unilateral deviations. Finally,
it reduces the search for rate-wise optimal feedback policies subject to
feedback constraints from function spaces to a finite dimensional Euclidean
space.Comment: Submitted to IEEE International Symposium on Information Theory, St.
Petersburg, Russia, Aug 201
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